Category Archives: Tutorials

Attached Images in WordPress using the_post_thumbnail

I’ve been working with WordPress for years now, and I’ve always struggled with an easy way to display an image that’s attached to a post in a list of posts. I didn’t say it wasn’t possible, just not easy. In the past I’ve used plugins, like "The Attached Image", or hacked my way around the issue. While these methods worked, they weren’t ideal, and any time you can avoid using plugins, the more healthy your WordPress site will be.

I was delighted then, to find that WordPress 2.9+ comes with a few new functions designed specifically for working with images attached to posts. Specifically, the_post_thumbnail works wonders. Here’s how it works:

Add Thumbnail Support

First, you have to activate post thumbnails for your theme. Open functions.php, and add this line somewhere near the top:

add_theme_support('post-thumbnails');
set_post_thumbnail_size(224, 126, true);

The first line adds thumbnail support to your theme. The second line overrides the "thumbnail" settings in your WordPress admin panel. The three values passed here are image width, image height, and the crop flag. If you set the crop flag to true, WordPress will automatically re-crop images so they’re not distorted.

Next, open any of your existing posts. You’ll be happy to find a new box in the right column, titled "Featured Image". You can then use the standard WordPress media tool to either upload a new image, or select an image from your site’s Media Library. Once you’ve associated a featured image with a post, the next step is adding it to your templates.

Insert Thumbnails in Your Theme

Locate the loop where you’d like thumbnail images to appear, and insert the following code:

the_post_thumbnail();

This will insert a full image HTML element, with the option to pass an array to specify dynamically generated attributes, like the image’s alt or title text.

Have More than One Size? No Problem!

Say you want to feature two thumbnail sizes on your site. Switch back to functions.php and add this code, below the code we added earlier:

add_image_size('thumbnail-50', 50, 50);

This cuts an additional image at 50×50 every time an image is uploaded to the WP Media Library. You can add as many sizes as you’d like. You can then add this call in any of your templates:

the_post_thumbnail('thumbnail-50');

Here you’re just passing the name of the thumbnail you assigned in functions.php, so WordPress knows which thumbnail to use. When the_post_thumbnail() is called with no argument, it will use the default size originally set in set_post_thumbnail_size().

There’s a lot more you can do with these new functions, including setting up conditional PHP during loops to display a larger image first, with smaller images for the second and subsequent posts, for example. I encourage further reading at the WordPress codex:

WordPress Codes: the_post_thumbnail()

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Access Remote XML via jQuery+AJAX with PHP as a Proxy

If you’ve ever had to work with XML from another domain, and only had JavaScript in your toolbox, you can feel my pain. Cross-domain XML has been the bane of my existence for many years now, when working on sites where there is no server-side scripting language available. jQuery has some great AJAX features, but you can’t make use of any of them if the file you’re trying to retrieve is an XML file on another domain. Until now. PHP is still required as part of this equation, but it acts as a web service, rather than residing on the server where your site lives.

Setting Up PHP as a Web Service

Thanks to a few new JSON functions added in PHP 5.2, we can build an XML to JSON web service in 4 lines of code. That’s right, 4 lines. Here it is, in all its glory:

$c = $_GET['car'];
$s = file_get_contents('http://www.example.com/' . $c . '.xml');
$a = json_decode(json_encode((array) simplexml_load_string($s)),1);
echo $_GET['callback'] . '(' . json_encode($a) . ');';

This code would reside on a server separate from the server where your site is hosted. And now the break down:

$c = $_GET['car'];

Get the value from the query string (browser’s url bar) with the name “car”, which we’ll see when we build the jQuery request, and save it in a variable named “$c”. Easy enough.

$s = file_get_contents('http://www.example.com/' . $c . '.xml');

Get the contents of a remote XML file, inserting the $car variable in the URL, and save in a variable named “$s” (for “string”).

$a = json_decode(json_encode((array) simplexml_load_string($s)),1);

Convert the XML string into a JavaScript array using PHP’s new json_decode and json_encode functions, and save this new array in a variable titled “$a”.

echo $_GET['callback'] . '(' . json_encode($a) . ');';

Here’s where the magic happens. We take that array, and convert it into JSON using PHP’s json_encode function. We also get the “callback” variable from the query string, which is required by jQuery, and append parentheses around the encoded JSON. The appended parentheses are also known as the “P” in JSONP, or “JSON with Padding”. What this does is essentially create a JavaScript function to pass back to your site that looks like this:

callback987986215(allyourJSONdata)

Setting Up jQuery to Call Your Web Service

Once you’ve got your PHP web service setup to convert XML to JSON, making the request in jQuery is pretty simple as well. Here’s how its done:

$(document).ready(function() {
	$.ajax({
		dataType: 'json',
	  	url: 'http://www.example2.com/my-web-service.php?car=mercedes&callback=?',
		success: function(data) {
			//parse your new JSON object here
		}
	});
});

This is a pretty standard jQuery AJAX request. The url paramater is the most important piece here. We’re looking for the JSON data on our server where our PHP service is hosted, and passing 2 variables:

  • car with a value of mercedes, and
  • callback with a value of ?

The variable of car=mercedes depends on the site where you’re pulling your XML from. This isn’t required, it just demonstrates how you could build a flexible web service to leverage for more than one external XML feed. The second variable callback=? is required by jQuery. The question mark is just there to append an additional name/value pair. jQuery will recognize the variable callback=? and replace the question mark with a randomly generated string of numbers. That’s why in your PHP web service, you get the callback variable, and send it back to jQuery as the function name. Its a sort of security measure.

That’s really it; from this point you have a jQuery object to work with containing all the data in the original XML file. You can see the jQuery object and all its pieces easily by setting a few breakpoints in Firebug and digging in.

If you want to get into the gritty details of how this works, like the coolness of how you can call functions in JavaScript by passing JSON as the argument, and how PHP can convert XML to an array and then to JSON, check out a few of the articles I referenced while building this:

How to Setup a Page-Driven Nav in WordPress 2.7

I’ve been working with WordPress for years now, and I thought it might be a good time to start sharing my knowledge of WordPress best practices.  One item that I think a lot of people just getting started using WordPress might find handy is how to build a navigation that is driven by pages.  Having a navigation driven by pages has numerous benefits, including having the nav written out as an XHTML compliant unordered list, being able to include or exclude any pages you’d like, being able to sort the list items to your preference, and being able to style the current page’s nav button differently.

Create those Pages

The first thing you need to do to setup a nav driven by pages is create the pages themselves.  The title you give the page will be the text that appears in the nav.  Also note that by default the nav items will be sorted alphabetically, but you can prioritize them setting the “Order” field from within each individual page.

The Magic of Template Tags

After you’ve created all the pages you’d like to include in the navigation, all that’s left to do is add the template tag to your template (usually in header.php).  The template tag that lists pages in WordPress is, you guessed it, wp_list_pages. Here’s a sample template tag included in my header.php file that passes a few parameters to the function:

<?php wp_list_pages('include=2,7,9,11&title_li='); ?>

The above block of code includes an opening php statement <?php, the function call wp_list_pages('');, and the arguments to be passed to the function include=2,7,9,11 and title_li=.

Let’s take a look at the two arguments I passed to the wp_list_pages function, starting with include=2,7,9,11.

This tells the function I’d like to include only pages with the id’s of 2, 7, 9 and 11. To find the page id’s that match your specific pages, go to your pages>edit screen and hover over the link for the title of the page, and (if you’re using Firefox) look at the bottom of your browser. At the end of the link you’ll see something like post=7. The number here is your page id. Plug in the page id’s for any pages you’d like to include, and you’re good to go!

The other argument I pass to the wp_list_pages function is to remove the title that would appear by default. By passing title_li= you’re essentially saying “set the title to blank”, and the function does not return a title list item. Generally you won’t want the title, which is up one level in the document tree, to appear if you’re making a navigation that you’ll end up floating to the left with CSS.

The ampersand between the two arguments just allows you to string together multiple arguments. You can string together as many as you’d like to further develop your own custom WordPress queries using any of the further options detailed on the WordPress.org wp_list_pages template tag page.

Check out the Coolness

The last, and probably most worthwhile thing about building your nav in WordPress using pages is that while navigating your site, the list will be auto-updated with a class that allows you to style the current page’s button to look different than the other nav buttons.  After you’ve got your nav set up and working, visit one of the pages and then view the page source.  You’ll see the class of current_page_item applied to the list item for the page you’re currently on, automatically generated by WordPress for each page.

Now just start styling your way to a dynamic WordPress page-driven navigation! If you need more info on the CSS required to float a list to the left that creates a horizontally oriented navigation out of an unordered list, check out this tutorial at 456 Berea St.

I hope this can help you to build your own navigation, and take it even further using the WordPress.org template tag page.

Review: Simply JavaScript by Kevin Yank and Cameron Adams

Book review of Simply JavaScript by Kevin Yank and Cameron Adams

Simply JavaScript by Kevin Yank and Cameron AdamsI read Simply JavaScript a few months back, and couldn’t help but include it in my reviews here at withinsight.com.  Its simply too good not to.  I’ve got a decent amount of JavaScript experience, although not necessarily through practice.  JavaScript has always been that part of my web design arsenal that I’ve wanted desperately to add, but has never seemed to work its way into regular usage in my day-to-day work.  You can’t say its for lack of trying, as I’ve read the first half of O’Reilly’s JavaScript, The Definitive Guide, which while full of great info, is not necessarily the best introduction to JavaScript for the beginning scripter.  I then found DOM Scripting by Jeremy Keith, which offers a very, very introductory level explanation of JavaScript before digging into the basics of DOM Scripting.  I had a decent picture of what else was out there in terms of JavaScript books.

Jeremy Keith is actually the one who recommended Simply JavaScript on his website a while back, which is how I originally heard about it.  He stated that his book DOM Scripting was intended for a very specific audience, and that there really weren’t any other books that did it as well as he does, until Simply JavaScript was released.  Very big of an author to acknowledge the competition with a tip of the hat.

Meet Your New Friend, JavaScript

If I could, I would probably go back and start from scratch originally with Simply JavaScript.  It is a perfect introduction for the web designer looking fill out the third leg of the XHTML/CSS/JS stool that we all sit upon.  Yank and Adams present the material in a way that anyone with a little XHTML and CSS experience will not only understand, but really find themselves enjoying.  I literally found myself laughing out loud at a few points, such as:

The popularity of regular expressions has everything to do with how useful they are, and absolutely nothing to do with how easy they are to use – they’re not easy at all. In fact, to most people who encounter them for the first time, regular expressions look like something that might eventuate if you fell asleep with your face on the keyboard.

Fantastic!  There are a number of moments like this that brighten up the pages.

Simply JavaScript is written in a progressive tutorial format, so you can move through it chapter by chapter, rather than using it as a reference.  The one exception to this is the chapter on “Errors and Debugging” which falls fairly late in the book.  I was okay without it for the first few chapters, but once I got into chapters 4, 5 and 6 on events, animation, and form enhancements, respectively, I think I could have done with reading that chapter first.  In chapter 7, they introduce the Firebug Firefox extension, and how to use it to pause the state of JavaScript at selected lines in your code, which I definitely could have used a little earlier in the book while troubleshooting projects.

JavaScript Libraries Galore

Another great aspect of Simply JavaScript is how they relate the tutorials completed in each chapter to the respective current JavaScript library.  So if you’ve heard about all the cool stuff web designers and developers have been doing with libraries like Prototype & script.aculo.us, MooTools, Dojo, jQuery, or Yahoo’s YUI, but haven’t been able to find practical uses for any of them in your projects, here’s where you can make the connection.

Yank & Adams build a very nice core library that you can use to power a few solutions to design problems that have faced web designers for years, like building stripey tables on the fly, or validating form information.  They even get into more advanced topics like animation and AJAX.  Actually, after you read this book, you’ll probably realize how non-advanced these topics are.  This book truly does make JavaScript simple!

I feel like a lot of JavaScript is like a catch-22 in that until you read a book like this, you have a very limited arsenal.  You may know how to pop open a new window or change the behavior of a few links, but you don’t truly have a grasp of the potential of what you can accomplish with JavaScript.  Reading a book like Simply JavaScript, even if you don’t go into all the details and grasp every last concept, at a bare minimum lets you know what you can do, which will help you tremendously in future projects.

First Impressions Make Such an Impact

One last thing that I need to mention is the production quality of this book. Sitepoint really went all out.  I’ve got six Sitepoint books, everything from HTML basics to PHP, and Simply JavaScript is the only one that is full color. In addition to brightening up the pages with color, the footnotes are all located at the bottom of each page.  I was recently reading the O’Reilly book AJAX Design Patterns, and found it extremely annoying to have to continually skip over URLs in the middle of the text.  Sitepoint places URL footnotes where they should be, at the foot of each page, making it easier to concentrate on the text and code, and reference the footnotes when you want to.

Overall, this is absolutely the best starting point for the beginner JavaScript student, and I would recommend it to any web professional who works with code on a daily basis.  It will teach you to apply the same unobtrusive principles that you hopefully already apply of CSS to XHTML documents, instructing you how to do the same with JavaScript.

You can purchase Simply JavaScript over at Amazon.com.

Rating

  • Overall: 9 out of 10

SXSW and jQuery

So right about now I’m wishing that if I could be anywhere, it would be at SXSW (South by Southwest).  For those of you who don’t know, its about the coolest festival on the planet.  And I don’t know from experience, just from colleagues and coworkers and podcasts and industry moguls giving me an earful.

In addition to being a hotspot for web design, SXSW boasts an impressive musical lineup each year, and this year I’ll be disappointed that I’ve missed The Everyday Visuals, Madi Diaz, and the undisputable heavyweight of soul, Miss Erykah Badu.

I’ve been hearing about it for weeks, from Paul Boag blabbering about it on his Boagworld podcast, to having to postpone projects with colleagues who are attending, to CSS guru Eric Meyer tweeting, “If you’re not going to SXSW, tweet like you’re there.  Nobody will know the difference.”  Yeah, that almost makes up for not being able to attend.

But alas, I am not one to linger, and the time spent here at home has given me the opportunity to start exploring jQuery, which was recommended to me by Alex King, famed author of the WordPress Popularity Contest plugin, and another item that Paul Boag has been going on endlessly about for months now.  I finally broke down and downloaded the library and started playing with it.

From my first impressions, Paul has reason to be going on endlessly.  It seems that the potential of what a web designer or developer can accomplish with the JavaScript library is in fact endless.  The first item that caught my eye was the fact that on the jQuery homepage they offer the expanded, developer version of the library, along with the compressed, production version.  I was immediately reminded of the hours I’ve spent testing the best method to minify, compress and serve my Prototype and Scriptaculous libraries.  jQuery does this for me?  Fantastic.

Second, I was really impressed with the quality and quantity of documentation.  Compared to Prototype, jQuery blows it out of the water in terms of a working online manual.  I think I’ve officially moved the “Prototype and script.aculo.us” book to the back of my “must read” list.  I’ve actually read the first half of it already, but it was cryptic and would have required re-reading on my part to fully absorb the material.  jQuery is the complete opposite.  There are video tutorials explaning the beginner steps.  Video tutorials.

The last thing about jQuery that really hooked me was the ease with which a web designer can pick up the library.  A lot of the arguments you pass to the library are the same as in CSS.  So if you’re looking for a div with the id of conference, you pass (“#conference”) as the argument.

It seems like its going to be really easy to quickly get up to speed with the library, and that it has a lot of power in terms of what you can do with it.  If you’re interested, check out the jQuery site, the jQuery UI site, as well as some of the video tutorials. Really, really, really cool stuff.

Installing WordPress MU on Mac OS X Leopard

I’ve run through this process a few times now, so I thought I’d document my steps for anyone who’s interested in setting up the multi-user version of WordPress on their local box for testing purposes.  The power of the multi-user version of WordPress is impressive, especially when combined with BBPress for forums, and the teetering-on-official-release BuddyPress for social aspects.  Ready to dig in?  Lets go.

The first thing you need to ensure prior to installing WordPress MU locally is that you have the underlying technologies installed.  WordPress and WordPress MU run on LAMP, or in this case MAMP.  There are all-in-one packages out there that install all three for you, and OS X does come with versions of Apache and PHP, but we want to learn how to get our hands dirty and be able to fix anything ourselves in times of crisis, right? So we need to make sure you’ve got Apache running, MySQL installed with a dedicated database setup, and PHP installed.

Turning on the Apache Web Server

First, we’ll tackle Apache.  This sentence will probably take longer to write than it will for you to turn on Apache on your Mac.  Go to System Preferences > Sharing > Web Sharing.  Checking of the “Web Sharing” checkbox here toggles the Apache server.  If you ever need to restart Apache, its as easy as coming in here, unchecking the “Web Sharing” checkbox, and checking it again.  Cake.

Installing MySQL

On to MySQL.  You’ll need to download the most recent version of MySQL, which can be found at the MySQL downloads page. Click “downloads” under the MySQL Community Server section.  Scroll down to the “Mac OS X (package format)” link and click.  Here is where you’ll have to ensure you download the proper package based on your Mac.  I chose the 10.5 (x86) since I’m running an Intel MacBook Pro, which ias the x86 processor. After you determine which package suits your Mac, click the “pick a mirror” link, and if you’ve never downloaded anything from the MySQL site before, you’ll have to register quickly.  Once you’ve registered and downloaded the dmg (named mysql-5.1.31-osx10.5-x86.dmg in my case), you’re ready to run the installer.

Once you’ve opened the dmg, you’ll see two .pkg files we’ll be interested in.  First, run the installer pkg file, which will walk you through a simple install.  After the initial install you’ll want to launch MySQLStartupItem.pkg, which will ensure that MySQL starts each time you restart your Mac. You’ve now got MySQL installed on your Mac!  Note the install location, as we’ll need that later on to create the database for WordPress MU.  Mine installed at /usr/local/mysql/bin/mysql.

Another item worth mentioning is that working with MySQL, PHP and Apache requires you to have access to a lot of OS X’s hidden files.  I recommend a great OS X app called FileXaminer, which I read about in MacWorld a while back.  FileXaminer lets you browse all the hidden files in Finder, and chmod the permissions on files and folders directly from Finder, rather than the command line.  Definitely a great solution for 10 bucks.

Installing PHP

The final piece of our MAMP stack is PHP.  PHP installation is fairly straightforward, and the best package online is located at Entropy’s PHP download page. There’s a box on this page titled “PHP 5 on Mac OS X 10.4, PPC and Intel”, and you can select the “PHP 5.2.4 for Apache 2” package.  Its definitely worth reading through this page first, but most users will have the default setup of Apache, and won’t need to make any changes prior to running the install.

After running the entropy installer, you can run a test to make sure everything went well.  Create a file titled test.php, and stick the following code in it: <?php phpinfo() ?>. Put test.php in your /Sites folder (/Users/yourusername/Sites), and then open up http://10.0.1.2/~yourusername/test.php.  The IP used in this example is found in System Preferences > Sharing > Web Sharing.

The phpinfo function is a great way to quickly check all the settings of your PHP install, so save this test file for reference in the future.

There’s one final tweak to PHP that’s really a best practice.  You’ll want to navigate to your php.ini file, and open it in your favorite text editor.  My php.ini is located at /private/etc/php.ini.  Make a duplicate of this file (sometimes the original will be called php.ini.default, so make a dup called php.ini).  Once you’ve opened the php.ini file, search for “register_globals = On”, and switch it to register_globals = Off”.  Also, search for “magic_quotes_gpc = Off” and switch it to “magic_quotes_gpc = On”.  In the php.ini file, all lines that start with a ; are commented out, so you’ll want to search for these two lines that are not commented out and then make the changes.

Save the changes in php.ini, then restart Apache in System Preferences.  Then open your test.php file again, and look for the changes to make sure they were made.

Installing WordPress MU

Finally, its time for the money melon.  Download the latest version of WordPress MU from the download page.  Unzip the package and stick it in your /Sites directory, and rename (I chose “wpmu”).  The first thing you’ll want to do before attempting to install WordPress MU is to open the README.txt file that is in the root directory of the unzipped WPMU package.  You’ll want to read this carefully and cater the specific files you your specific install case, but they basically touch upon the php.ini file that we’ve already edited, and the httpd.conf file, which is Apache’s root config file.  I found mine located at /private/etc/httpd.conf.  You can find a better understanding of the Apache httpd.conf file, the directives contained within, and an explanation of the .htaccess files you can use to override the httpd.conf file in your local sites at the Apache web site.  I found that after reading a few short pages here, that the Apache config file cascade is very similar to the cascade of CSS files and rules.  Cool stuff.

Creating a MySQL database

Once you’ve read through the README.txt and made appropriate changes to your php.ini and httpd.conf files (and taken decent notes, hopefully), you’re ready for the install.  Since you’ve already got the files unzipped in your /Sites directory, the next step of the install is creating the database. Open the Terminal application (Applications > Utilities > Terminal), and type the following command:

/usr/local/mysql/bin/mysql -u root -p

where the path matches the MySQL path I mentioned to remember earlier.  The -u root tells MySQL that you want to login as “username root”, and the -p tells MySQL to prompt you for a password. If you’ve never logged into MySQL in terminal before, the username for root will either be root or blank.  After you’ve successfully logged into MySQL, you’ll know as the command prompt will have changed to:

mysql>

To create a database, type the following command:

CREATE DATABASE wpmu;

where wpmu is the name of the database.  You can name the database whatever you’d like, but make sure to follow it with the semi-colon, and remember the name of your database.

While we’re in here, its probably a good idea to change your root username.  Type the following command:

UPDATE mysql.user SET Password=PASSWORD(“new password”) WHERE User=”root”;

Replace the new password with your desired password.  Once we’ve created the database, and updated the root MySQL user’s password (and noted both), we can exit MySQL by typing:

exit

Running the WPMU Installer

You can now open the index.php from your wpmu folder in your web browser.  It may tell you that you have to change the permissions on a few folders prior to running the install.  If this occurs, it is extremely easy to modify the permissions using FileXaminer.  The two folders you’ll have to mod are the root /wpmu folder and the /wp-content folder, changing the permissions on both from 755 to 777.  After you’ve made these changes, refresh the index.php file, and enter the proper information.

Since WPMU doesn’t allow you to install at “localhost”, and you have to use “localhost.localdomain”, I had to make a change in my hosts file as well.  The file is located in /private/etc/hosts, and I changed:

127.0.0.1 localhost

to

127.0.0.1 localhost.localdomain

and resaved the file.  Also note that I set the database location to “localhost.localdomain”.  The other information on the install screen should be pretty simple; the database name and password we just created in MySQL.  Once you’ve filled out the form, submit and you should be looking at a nice, fresh, local install of WPMU.

If you do get stuck, the WPMU Forums are a big help, as most likely users have run into your same problem. The steps above worked for me, but there may be variables with your certain configuration that you’ll need answered in the Forums.

Good luck, and happy WPMU’ing!

UPDATE 3/4/09: If you’d like to configure OS X Leopard to host multiple local WordPress instances, follow this great tutorial at O’Reilly.  I’ve spent hours piecing together solutions from various articles, but this O’Reilly article sums it up great.  Basically, I’ve now got WPMU running locally at test.wpmu.local, and WordPress running locally at test.wp.local.  Apache’s Virtual Hosts are really powerful, and essential if you’re going to be working on multiple client websites that run on WordPress.